Chromosomal Damage Induced by Herbicide Contamination at Concentrations Observed in Public Water Supplies

Abstract

Herbicide contamination of natural resources, specifically groundwater, has drawn considerable public attention in recent years. Although deleterious effects of herbicides at large dosages have been well documented, information is lacking about the possible effects of herbicide levels that are found in public water supplies. Chromosomal damage is examined by flow cytometry on Chinese hamster ovary (CHO) cells that are exposed to three herbicides (atrazine, simazine, and bentazon) at concentrations deemed safe by the U.S. Environmental Protection Agency (USEPA) for drinking water. A known clastogen (ara-C) is also included as a reference for comparing the magnitude of chromosomal damage caused by herbicides. Chromosomal damage was assessed by measuring the coefficient of variation (CV) and percent chromosomes present in the larger chromosome distribution peaks. Exposure to atrazine (6-chloro-A L ethyl-W-(l-methylethyl)-l,3,5triazine-2,4-diamine) increased the CV of the largest chromosome distribution peak at concentrations considered safe by the USEPA. Chromosomes exposed to both simazine (fi-chloro-A^W-diethyl-l^Striazine-2,4-diamine) and .bentazon (3-(l-methylethyl)-(lff)-2,l,3benzothiadiazin-4(3/?)-one 2,2-dioxide) did not exhibit chromosomal damage. Further analyses carried out on atrazine concentrations about equal to levels found in public water supplies revealed the potential of atrazine to induce chromosome breakages in CHO cells. Atrazine concentrations that were manyfold greater than the contamination limits exhibited a true clastogenic nature like ara-C. The results provide evidence for further investigations as to the potential health risk of consuming water contaminated with atrazine.

Persistence of pharmaceutical compounds and other organic wastewater contaminants in a conventional drinking-water-treatment plant

“…Moreover, drinking-water criteria currently are based on the toxicity of individual compounds and not combinations of compounds. The possibility that exposure to multiple organic compounds, even at low concentrations, may have a synergistic humanhealth consequence is an area of recent research (Birader and Rayburn, 1995;Marinovich et al, 1996), and the co-occurrence of organic compounds in drinking-water supplies has recently been documented (Stackelberg et al, 2001;Squillace et al, 2002). In this study, 11-17 different OWCs were detected in each of the four samples of finished water.…”

Herbicides and the Aquatic Environment

“…The herbicide atrazine is classified as a toxic agent, carcinogen and hormone disrupter (Friedmann, 2002) which includes potentially carcinogenic compounds to humans (Biradar & Rayburn, 1995). The presence of this product in the environment presents a risk to wildlife and the ecosystem in general, interfering with hormonal activity in animals and human in low doses.…”

The Clastogenic Potential of Triazine Herbicide Combinations Found in Potable Water Supplies

“…The separation of the chromosomes and breakage of the cells was achieved by pushing the sample through a 22-gauge needle. The procedure was adapted from Biradar and Rayburn (11). The chromosomes were then analyzed on a Coulter EPICS 750 series flow cytometer-cell sorter.…”

“…Cultures were maintained by adding 0.5 ml cell suspension to 9.5 ml complete medium in petri plates (100 x 15 mm). To treat the cells, the three herbicides atrazine [6- (5,11). The herbicides were mixed at the MCL concentrations: 3 ppb (0.003 xg/ml) for atrazine and cyanazine (no MCL for cyanazine is set, so the same level designated for atrazine was used), and 1 ppb (0.001 ig/ml) for simazine, as well as the highest levels found in Illinois water supplies: 18 ppb (0.018 pg/ml) for atrazine, 12 ppb (0.012 pg/ml) for cyanazine, and 4 ppb (0.004 pg/ml) for simazine.…”